1. Field of the Invention
The invention is directed to a brush seal having a front panel or plate and a supporting or bearing plate.
2. Description of the Prior Art
Many different brush seals are known that, for example, are utilized in gas turbines in order to seal the interspace, which is between a housing and a rotor rotating at a comparatively high speed, against leakage. Given such seals, the ends of the bristles, which are combined to form a dense bristle packet, project beyond an inside edge of the supporting plate and thus seal the interspace, which is to be kept optimally small, between the inside edge of the supporting plate and the rotor surface. When a high differential pressure is adjacent the seal, then the supporting plate arranged at the low-pressure side supports the bristles to prevent sagging toward the low-pressure side.
For manufacturing a brush seal essentially composed of a front panel, a supporting plate and a bristle packet are arranged therebetween, welding methods were previously utilized with which, in particular, the front panel and supporting plate, which form a seal housing, are welded to one another.
Given a brush seal disclosed by European Patent Application 0 453 315, for example, the front panel, the bristle packet and the supporting plate are connected with a weld that extends over the outer circumference of the brush seal. Since the outer circumferential surface is a fitting surface and must proceed planarly and perpendicularly relative to the two outer lateral surfaces of the front panel and of the supporting plate for an exactly fitting arrangement of the brush seal with reference to the housing and to the rotor, additional processing steps, for example grinding, are necessary due to the weld. This leads to higher manufacturing costs and longer throughput times during manufacture.
It also proves disadvantageous when using the welding processes that the comparatively thin front panel and supporting plates frequently warp due to non-uniform temperature distributions.
German Patent Document No. DE 39 07 614 Al discloses a brush seal having a wire bundle held in a slotted tube, wherein the tube is held together by two supporting rings joined to form a housing by one or more clamp lips that are attached to the one supporting ring and embrace the second supporting ring at the outside to produce a clamping force. The positioning of the clamp lips ensues with a curling or rolling process. The manufacture of the two supporting rings is not disclosed, nor is the provision of a fit surface at the brush seal housing.